Engine Rigging Checks And Adjustments; Ground Idle Adjustments; Flight Idle Adjustments - Thrush Aircraft S2R–T660 Maintenance Manual

THRUSH AIRCRAFT INC - T660 TURBO THRUSH
Upon completion of rigging and prior to engine running, a functional check of the system's operation
should be carried out. This check should include the operation of all controls throughout their entire
operating range and checking for freedom of all movement, freedom binding, security and safety.

ENGINE RIGGING CHECKS AND ADJUSTMENTS

This section details various engine and propeller functional checks, which are performed after
engine control rigging and engine run up.
GROUND IDLE ADJUSTMENTS (Ref. Fig. 4-7)
A. Run engine to bring oil temperature within normal operating ranges (38
B. Set condition lever to LOW-IDLE. and power control lever in IDLE. Check Ng tachometer
for a reading of 59% Ng for PT6A-45 and PT6A-67AG or 62% Ng for PT6A-60AG. If it is
not, proceed as follows:
1. Loosen FCU lever clamp screw (Detail A) then loosen the upper low idle
adjustment screw and tighten the lower low idle screw by an equal number of turns
to INCREASE idle speed. One flat allen head screw will change idle speed 4%.
2. Tighten the FCU lever clamp screw.

FLIGHT IDLE ADJUSTMENTS

A. Set condition lever to HIGH-IDLE. Condition lever (Fig. 4-3, #8) must contact HIGH-IDLE
stop screw (Fig. 4-7). An angle of 42 degrees +/- 4 Degrees represents the angle formed
between the CUT-OFF and HIGH-IDLE positions at the lever.
B. Set HIGH-IDLE to 69% Ng. Adjustments can be made by turning nuts on the cam follower
assembly (Fig. 4-7). Adjusting the nuts out will rotate the FCU lever (Fig. 4-3, Item 10) in a
clockwise direction and increase Ng and conversely, turning the nuts will increase or
decrease HIGH-IDLE speed by 1.5%. (Note: PT6A-45, and PT6A-67AG High-Idle are
adjusted by turning High-Idle Stop in to increase, out to decrease RPM.)
Effective: 12/17/03
AIRCRAFT MAINTENANCE MANUAL
*NOTE*
After adjusting idle, MAX FORWARD and MAX
REVERSE settings may require readjustment.
C minimum).
°
4 – 30